1. Field of the Invention
The present invention relates to a cable structure, more particularly to a cable structure capable of preventing a second insulation layer from retreating into a first insulation layer.
2. Description of Related Art
A power cable is commonly seen in daily lives, for example being served to connect a round-column type power supply plug, and according to different diameters of power sockets of various electronic good, e.g. a notebook computer or mobile phone, the power supply plug may have different outer diameters. Or one end of the power cable is designed to be a strain relief (SR) of an electronic goods, e.g. a power adapter.
In view of the whole structure of the mentioned cable, the cable includes a metal anode conduction wire, a metal cathode conduction wire and a signal wire, wherein the metal anode and cathode conduction wires are metal interlacing wires without insulation layers, and the signal wire is covered by an insulation layer. In the processing formation period of the cable, the anode conduction wire is interlaced on the signal wire, then a layer of insulation material (a second insulation layer) is covered on the anode conduction wire, and the cathode conduction wire is interlaced on the insulation material, then another layer of insulation material (a first insulation layer) is covered on the cathode conduction wire, so as to complete the assembly of the cable.
If the mentioned cable is desired to be connected with a power supply plug, a portion of the first insulation layer is firstly peeled so the second insulation layer and the cathode conduction wire are exposed; then a portion of the second insulation layer is peeled so the anode conduction wire and the signal wire are exposed, and a heat shrinkable sleeve is respectively installed on the anode conduction wire and the cathode conduction wire and the heat shrinkable sleeve is processed with a heating treatment, so that front portions of the anode and the cathode conduction wires and the signal wire are able to be welded on corresponding positions of the power supply plug, then the cable and the power supply plug are processed with an injection covering operation, so the finished goods of the power supply plug is provided with functions of transferring DC power and signals.
The concerned disadvantage of the mentioned cable is that, when the cable is being used, the second insulation layer retreats toward the first insulation layer due to the pull or swing movement done by users, but the heat shrinkable sleeve installed at the exterior of the anode conduction wire does not retreat with the second insulation layer, so the anode conduction wire inside the second insulation layer is exposed and may cause short circuit with the cathode conduction wire. So how to prevent the second insulation layer from retreating into the first insulation layer is needed to be solved.